Quick Facts

Quick facts

• Small-seeded Dodder (Cuscuta planiflora) is a parasitic annual herb with slender, twining, crimson to yellowish coloured stems and small white flowers.
• Spreads mainly by seed which can remain viable in the soil for up to twenty years.
• Lives entirely on the host plant and reduces the growth and yield of the host.
• Is naturalised in Western Australia, South Australia and Victoria.
• Has the potential to become a serious agricultural and environmental weed in Australia.

What Does It Look Like?

What is it?

Small-seeded Dodder (Cuscuta planiflora) is an annual, parasitic herb that completely lacks chlorophyll. The slender, thread-like stems are up to 0.3 mm wide, crimson to yellowish in colour and hairless. The stems twine around host plants eventually forming a tangled mat and penetrate tissues of host plants with wart-like suckers (called haustoria) to obtain water and nutrients. The leaves are absent or reduced to minute scales.

The tiny, mostly white, flowers are arranged along the stems in small compact clusters up to 6 mm in diameter. Each flower has five sepals and five petals. The triangular sepals are shortly fused at the base, fleshy towards the tip and are slightly shorter than the petals. The petals measure 1.5–2.5 mm long and are fused for about half their length to form a bell-shaped corolla with five spreading triangular lobes. The corolla lobes are fleshy and swollen at the tip.

The small fruits are 1 to 1.5 mm across and split around the base to release up to four seeds. The seeds are about 1 mm long (Yuncker 1932; Johnson 1986; Pratt 2002).

For further information and assistance with identification of Small-seeded Dodder contact the herbarium in your state or territory.

Flower colour

White

Growth form (weed type/habit)

Vine

Where it currently grows? Preferred habitat

Small-seeded Dodder grows in a wide range of vegetation types and environmental conditions. In Australia, it is recorded growing on plants in gardens, lawns, on agricultural crops as well as native plants in natural vegetation. It has been found parasitising agricultural crops (such as canola and lupins) and native species including Goodenia (Goodeniaceae), Glischrocaryon (Haloragaceae) and number of native daisies (Asteraceae). Its potential host range is most likely significantly greater than it's current host range (Pratt 2002; Western Australia Herbarium 2007). Overseas records of host plants include Citrus (Rutaceae), Grapes (Vitaceae), many legumes (Fabaceae), solanaceous vegetables (Solanaceae), Chrysanthemum (Asteraceae) and Cucumber (Cucurbitaceae) (Pratt 2002).

Are there similar species?

Superficially Dodders (Cuscuta species) are very similar and can be difficult to distinguish. In Australia there are five naturalised and four native species (Johnson 2007, pers. comm.). Small-seeded Dodder can be distinguished from them by the following combination of features: small flowers (corolla 1.5–2.5 mm long) that are arranged in small compact clusters of up to 6 flowers and linear stigmas (female part of the flower) (Yuncker 1932; Johnson 1986; Jeanes 1999).

Why Is It A Weed?

What are its impacts?

Agriculture: Small-seeded Dodder as with other Dodder (Cuscuta species), does not generally kill the host plant (Cudney 1992). However, infestation in commercial crops results in yield losses and may cause reduced crop marketability. There are reports from overseas of intestinal disorders and poisonings of livestock from ingestion of Dodders, but there is little firm evidence that this is a significant impact (Parsons & Cuthbertson 1992; Holm et al. 1997). Although mostly palatable to livestock, infestations of Dodder do reduce the quality of pastures (Cudney 1992).

Native ecosystems: In areas of native vegetation it has the potential to significantly impact of the biodiversity (Pratt 2002). Dodders have been reported to also transmit virus diseases in certain crops (Parsons & Cuthbertson 1992).

How does it spread?

Small-seeded Dodder, as with other Dodder (Cuscuta species), is primarily spread by seed. The small seeds can be dispersed through water movement and movement of soil containing seeds by animals and machinery. They are also known to be distributed through contaminated agricultural produce such as fodder and crop seed (Pratt 2002). Dodder species are sometimes also spread by stem fragments on farm machinery or water. Seeds may potentially pass through animal digestive systems in a viable state and be spread through movement of stock or wildlife, or their manure (Parsons & Cuthbertson 1992; Pratt 2002).

What is its history in Australia?

It is not known exactly how Small-seeded Dodder was introduced to Australia but it was first recorded in Australia in 1947 from Fitzroy Gardens, Melbourne (Pratt 2002). Small-seeded Dodder was first recorded in Western Australia north-east of Geraldton in 1970 (Western Australian Herbarium 2007), and in the south east of South Australia in 1982 at Fairview Conservation Park. In 2001 the species was found in Australian Canola and Lupin crops for the first time (Pratt 2002).

How To Manage It?

Best practice management

Small-seeded Dodder, as with most Dodders (Cuscuta species), is a difficult weed to eradicate once it is present in an area.

Non-chemical control: Prevention of introduction and spread is a vital part of control and management of the plant. Movement of contaminated agricultural products (including fodder and livestock) that can introduce the plant to unaffected areas should be avoided. Livestock that have been grazing in contaminated areas or fed contaminated fodder should be quarantine for a sufficient period for seed to pass from their system before movement into uncontaminated areas. Mechanical control: Machinery can also spread the seed to new areas. All equipment should be cleaned prior to leaving infested areas (Pratt 2002).

Land management: In infected areas the containment and prevention of the development of a soil seed bank is an important aspect of managing dodder infestations. The selection of less susceptible or resistant crops and crop timing can be useful strategies in reducing seed production and further spread. Other management tools include burning, slashing, repeated tilling and herbicide treatments (pre-emergence and late season treatments (Pratt 2002).

Chemical control: The use of herbicides alone is frequently ineffective in the control of dodder species (Pratt 2002). An integrated approach including herbicide treatments has been considered beneficial in reducing soil seed bank of Large-seeded Dodder (Cuscuta indecora) in California (Cudney et al. 1992). There is a wide range of herbicides known to control Dodder species in a variety of crops, with varying levels of effectiveness (Pratt 2002).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Small-seeded Dodder as with other Dodder (Cuscuta species) has seeds that can remain viable in the soil for 10–20 years (Cudney et al. 1992; Pratt 2002). They can germinate throughout the year, without stimulation by a host species, providing the environmental conditions are suitable for germination and growth. The seedlings do not produce roots, but instead have a single stem that develops upward and twines around any nearby vertical object. The stems require contract with a suitable host within several days of germination, otherwise the seedling will die. Dodder grows rapidly after attachment and the basal part of the Dodder below the point of attachment soon shrivels away so that no soil connection exists and the parasite is completely dependent on the host for nutrients (Pratt 2002).

In Australia, flowering has been recorded from July through to April (Weber 1986; Jeanes 1999; Western Australia Herbarium 2007). Seed set occurs within a month of flowering. Dodder dies off annually with senescence of the host or in response to frost (Pratt 2002).

Where Is It Found?

Which states and territories is it found?

SA, VIC, WA

What areas within states and territories is it found?

Small-seeded Dodder is naturalised across southern Australia. In Western Australia it is recorded from Shark Bay southwards to near Bunbury and eastwards to Meekatharra and Leonora (Western Australian Herbarium 1998 – ). In South Australia it is recorded in the south east of the State from near Naracoorte and Robe (State Herbarium of South Australian 2007). In Victoria it is known from around Ballarat, Lake Corangamite and near Laverton (Jeanes 1999).

Small-seeded Dodder's potential distribution in Australia is unknown. However, coastal and high rainfall areas of southern Australia and inland areas of Queensland are considered at most risk from infestation by this species (Pratt 2002).

Where does it originate?

Small-seeded Dodder is a native of the Mediterranean region. It has become naturalised in more than 40 countries throughout the world (Pratt 2002).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, QLD, SA, TAS, VIC, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Cuscuta planiflora

Other scientific names (synonyms)?

Does it have other known common name(s)?

Small Seeded Alfalfa Dodder, Red Dodder, Strangle Weed Dodder, Alfalfa Dodder